Method of and apparatus for measuring superficial areas



c. E. LUCKE. METHOD OF AND APPARATUS FOR MEASURING SUPERFICIAL AREAS.

APPLICATION FILED JUNE 21, I9I5.

Patented Nov. 9, 1920.

3 $HEETS-SHEET I.

; Ill/VENTOR A? 6/ .1 Z Q 0 ,1 A; ATTORNEY C. E. LUCKE.

METHOD OF AND APPARATUS FOR MEASURING SUPERFICIAL AREAS.

APPLICATIONE|LEDJUNE21.I915.

w 4m 9 W mf /m W; M M Nm m w I n M 7 w .y

C. E. LUCKE.

METHOD OF AND APPARATUS FOR MEASURING SUPERFICIAL AREAS. APPLICATION EILED JUNEZI, 1915.

1,858,086. Patented Nov. 9, 1920.

3 SHEETS-SHEET 3.

.L i 1 0 0 O o o o o o o o o I I? 1 WI I 50 L9 6/ 6 lNVENTOR I w: ar/c {MW I W7 A; ATTORNEY cHAnLns n. LUCKE, OF NEW YORK, N. Y.

merrier) or AND APPARATUS roa MEASURING SUPERFIGIAL AREAS.

Specification of Letters Patent.

Patented Nov. 9, 1920.

Application filed .Tune21, 1915. Serial No; 35,262.

To all whom it may concern:

Be it known that I, CHARLES E. LUCKE, a citizen of the United States, residin at New York city, in the county of New ork and State of New York, have invented certain new and useful Improvements in Methods of and Apparatus for Measuring Superficial Areas, fully described and represented in the following specification and the accompanyin drawings, forming a part of the same.

I his invention relates to the measurement of superficial, or surface, areas, and comprises a method wherein the surface to be measured is placed against a measuring surface of definite size and of uniform permeability, and the area of the surface to be measured is determined from. the change in aggregate permeability of the measuring surface due to the presence thereagainst of the surface to be measured. The invention also comprises an apparatus or machine whereby surfaces may be measured in accordance with my method, and which comprises a supporting surface of uniform permeability against which the surface to be measured may be placed, means for maintaining a difference in pressure of air or other fluid on opposite sides of the measuring surface, and measuring means the indications of which are controlled according to the aggregate permeability of the measuring surface, all as will be hereinafter more fully explained and as claimed.

The object of the invention is especially to provide for the convenient and accurate measurement of the area ofsurfaces of irregular shape, and the invention has been inadeespecially with the idea of providing for the measurement of hides and other irregular shaped sheets or pieces of leather; but my method and apparatus may of course be used for measuring surfaces of regular shape, and the invention may also be used for measuring surfaces of other substances and materials in sheet or other form to the measurement of which the invention may be found adaptable. I

The aggregate permeability of a permeable plate of uniform permeability per unit area is proportional to its area. If air is sucked through such a permeable plate of uniform permeability per unit area, the amount of air flowing through the plate under a given vacuum will depend upon the size or aggregate permeability of the plate, and conversely the vacuum required to maintain a placed, the surface to causing the flow given flow through the plate will also depend upon the size or aggregate permeability of'the plate. If a sheet of impervious material, such as a piece of hide or leather, be placed against the outer surface of such a plate of uniform permeability, the aggregate permeability of the plate duced in proportion to the area of the sheet placed thereagamst; and with a plate of defimte slze, the flow under a given vacuum or the vacuum required to maintain a given flow, Wlll depend upon the size of the sheet placed agamst the plate, or the area of the uncovered portion of the plate; that is, the flow 1s a function of the vacuum and'the area of the uncovered portion aggregate permeability.

with the sheet will be re-' of the plate, or its: Y

the flow and the ag re ate ermeabilit of the plate with the she et against it. y change 1n aggregate permeability of a per-- meable supporting plate of definite size and of uniform permeability per unit area when an 1mperv1ous surface is placed against it, being thus readily measured, furnishes a basis for readily determining the area of surfaces of sheets or other bodies capable of being brought against the supporting or measuring surface of the plate; and this is the foundation of my method.

By causing the flow of air or other fluid through the supporting or measuring plate to be in the direction from the surface agamst which the surface to be measured is be measured is automatically drawn and held against the measuring surface by the difference in pressures maintained on the opposite sides of the supporting plate. The pressure difference for through the plate may be secured by excess plate against which the surface to be measured is placed, but this is inconvenient, and

the use-of suction means-for maintaining a vacuum on the opposite side of the plate is therefore preferred. I

The permeable'supporting plate may be of any suitable character. The closer the passages through the plate, and for a given aggregate permeability the finer the 1 pas-' sages, the more accurate will be the results obtained; but theconstruction of the plate, size of the passages and relative aggregate cross-sectional area of the passages and of the solid portions of the plate will, however, be governed largely by the uses and condi The pressure on the side of the tions for which the apparatus isjntended.

The surface of the plate may be'shaped to conform'to the shape of the surface to' be measured, but for general use in measuring pieces of hide or leather or other flexible-V sheets fiat or cylindrical surfaces are conveniently employed. If the surface'to be measured is inflexible,

tisin my method, such a description will:

. accompanying drawings 2- the measuring surface should be of suitable yieldin 'material so that it may accommodate itsel' to slight unevennesses in the surface to be measured.

As a full understanding of the'rnvent on can best besgiven by a detailed descr1pt1on' of the construction and use of an' approved apparatus embodying the apparatusfeatures of the invention and suitable for use in prac now e given in connectionwith the accom panyin' drawings illustrating such an appa. ratus in several alternat ve. forms-. ,In ithe Figure 1 terial of irregular or other-shapes;

Fig. 4 is'a view partly m partly in elevation of'anotherfonfidi app ratus;

Fi of 4;

Fig. 6 is a similar view taken on lined- 6 I of Fig.4;

Fig. 7 is a sectional viewtaken son-line 7-7 of Fig. 4;

- Fig. 8 is a View partly-1n SBCtlOII and partly inelevation illustrating another form ofaparatus; Figs. 9 and 10 are g ig. 11 is a plan view of another form of apparatus; and j detail sectional view of a por-,

Fig. 12 is a tion of a supportlng plate or bed having 'a g 1 should be-as narrowias consistent with the agrequiredlstren'gthand f rigidity, and the yielding surface. Referring to the drawings, and first rigs. 1, 2 and 3, the apparatus .shownwin these figures comprises a fiat permeable su leads tothe intake pipe 13 of an exhauster 14. The exhaustermaybe of any suitable type, but as here shown is a constant speed 4 ositive porting'plate 10 which forms theupper. s1 e of a suction box 11' fromwhich a pipe 12 blower and a regulating or ad uStmg valve 15- is interposed between the suction chamber and the exhauster. The Valve]v l5'would notbe necessary with an'adjust able orvariable capacity e'xhauster as such 5 an exhaus'ter alonegwoul'd-provide adjustable or re'guljatable means for exhausting air throu h an-a descri ed. .,'A vacuum age 201s connected with the vacuum cham er.

Th 0 permeable supporting plate 10, the upper s de of which provides the permeable supportingfland measuring surface, may be ri fflany suitable =:material and. construction.

is a perspective view ofan apparatus intended especiallyfor .the measure-7.? 1 ment of hide andother largesheets of'ma;

ection'tand i '10 "ments arewell met'by forming the plate as shown of a .pluralit' g of thin bars of suitable metal set pn e ge, or flatwise to each 5 is'an end view taken b 'jlin 5 5] other,

,fromthe suction chamber. A flow meter is connected with a pipe 16 leading from the discharge of the exhauster, this flow meter which air isexhausted from the suction box, that is, the rate atwhich air is drawn into the boxthrough the permeable latelO or justable opening ereinafter apparatus-shown in Figs. 1, 2 and 3 is ed'fformeasurin'g large surface areas uchfl; as-the surface areas of'whole hides, and:nius't," therefore, be; off comparatively i large size," say for-example, 10ft. long b 8;.ft.}-jwide, an .of-corresponding and su cie'nt strength-','-lwhile at the-same time the ores or passages 'thro'u the plate must orlaccurate results be 0 ,uniform size and closely and uniformlyispaced, and they eg'ate permeability offt -he plate shall not so reatasito requirethe use ofa blower 11m ue size. The conditions and requireand equally spaced apart. In the apparatus shown, the ends of the bars 22 rest on supporting shoulders provided by flanges 23,-;extending' from opposite sides of the suction box, -and the bars are spaced apart byspacing pieces'24 between the ends of adjacent bars. the whole series of bars being; pressed tightly together sectional viewstaken respectively on lines 9-9 andflO-lO of openings 'or' slots between the ba-rs .-.should ,be-only a small fraction ofjthethickness of the: bars,

as an example, "for 'a permeable be half plate 8x10.ft. in size {the bars ma an inch thick and twoinches s aced-one-tenthof an inchlapart. d tion "to' other advantages, of forming the gpermeable plate of spaced bars as' shown, this construction has the advantage that the slots or ,passages may be 1 readily cleaned by simplypassmg between-the bars a clearing piece of suitable thickness, and may be "morej thoroughly cleaned by removing the bars box. The-bar's the appaand v 11 adratus shown are obviously readily removable and replaceable.

With the measuring surface of the plate 10 entirely unobstructed, operation of the exhauster 14 will create a partial vacuum'in the suction box which will cause an indication by the gage 20, and the air drawn through the plate 10 will be discharged through the pipe 16 causing an indication by the gage 18 of the flow meter. If then something to bemeasured, such as a hide or piece of leather, be placed on the measuring surface wholly within'its limits, the portion of the surface covered by the hide will be closed, that is, the aggregate permeability will be reduced in proportion to the area of the hide, and there will result a new series of readings of the vacuum gage and flow gage, and from such change in the readings ofthe two gages, or from either one if the adjustment of the exhausting means remains unchanged, the area of the closed portion of the measuring surface, that is,,the area of the hide or other thing placed thereon may be determined. If, however, after the hide is placed on the measuring surface, the exhaustlng means be adjusted to increase the fl0w,(by, further opening the valve 15 in the apparatus shown or by speed increase with a variable speed exhauster) until the reading of the flow scale is returned to what it was before the hide was placed, then the vacuum will be increased and the area of the hide may be determined from the reading of the vacuum gage alone; or if the exhausting means be adjusted to reduce the vacuum until the original reading of the vacuum gage is restored, then the area of the hide may be determined from the reading of the gage of the flow meter alone.

he two gages may thus either one alone or both to ether be marked to read directly in terms 0% square feet or other unit of surface measurement to show the area of surfaces being measured by first placing on the measuring surface a series of surfaces of known area, provided that the exhaustion is maintained constant. The areas of surfaces of unknown 'area may then be read in terms of square feet from these empirically calibrated scales, takin them separately or together. The necessity of maintaining conmeans. Then the flow scale ma be marked for reading in terms of area'of s'urfaces to be measured by placing a series of surfaces of known area on the measuring surface and for each one adjusting the exhausting means to reduce the vacuum scale reading to zero; and similarly the vacuum scale may be marked to read in terms of area of surfaces bemg measured by adjusting the exhausting means to reduce the reading of the flow scale to zero for each of the series of surfaces of known area placed on the measuring surface. Either or both of the scales might be so marked with experimentally fixed calibrations, and 1n using the apparatus with either or both of the scales so marked it is only necessary when a hide or other thing is to have its surface measured to place the hide on the measuring surface and then adust the exhausting means to reduce the vacuum gage to zero readin if the area is to be read from the flow sea e, or adjust to reduce the flow gage to zero reading if the area is to be read from the vacuum scale.

The vacuumbox of the apparatus shown is also most desirably provided with a variable or regulatable auxiliary opening formed as shown by an opening 28 in one of the sides of the box provided with an adjustable sliding cover 29 and with a scale registering with the opening. This opening will be equivalent in its effect on the vacuum in the vacuum chamber and on the flow throughthe flow meter of a certain unobduce the variations in the readings of the vacuum and flow gages. When used for this stant exhaustion is avoided, however, and

greater accuracy and simplicity of reading secured by following the method of ad usting the exhausting means after placingthe surface to be measured against the measuring surface to reduce either one of the scale operation, both scales may be marked with a zero point for the reading when the measuring surface is entirelyun'obstructed and with acertain adjustment of the exhausting purpose, in measuring a hide having an area greater than a certain area the size of the opening is'adjusted to correspond in its effect on the vacuum in the vacuum chamber and on the flow through the flow meter to such certain area of the measuring surface so that the vacuum and flow gages then measure only the amount of surface area of the hide in excess of such certain area, and the total surface area of the hide being measured is obtained by adding the area obtained from the gages to such certain area. By making use of the Variable opening in this way, the limits of the readings to be taken from the vacuum and flow gages, or from whichever one is used to indicate the area of surfaces being measured, are reduced, thus making it more practical and convenient to use in the apparatus a vacuum gage or a flow gage or both of suitable kind aving amagnlfied or extended scale so that more accurate readings may be obtained. When used in this way, the variable opening may be considered as a means for reducing the range of gage readings, or as a means for reducing the gage readings by an amount equivalent to a certa n surface area; and obviously, for this purpose mst'eadof a variable opening such as shown, an opening which may be c osed or opened to one delinite size maybe provided. So also a variable auxiliary opening might be made use of in this way in the apparatus by ad usting it to correspond not only wlth one certain area of the measuring surface, or of surfaces to be measured, but it might equally well be adjusted for any one o a number of certain areas according to the size of (hiferent surfaces being measured,

Among other purposes which may be served by the variable opening 28, the following may be pointed out: With a constant exhaust, the reading from the scale of the variable opemn may serve in place of-the fiow meter rea ing to indicate the area of a surface being measured when the opening has been adjusted to reduce thereadmg of the vacuum scale to zero, or may serve 1 n place of the vacuum gage reading to 1nd1- cate the area of the surface being measured when the opening has been adjusted to reduce the reading of 'the flow scale to zero, thus avoiding the necessity for the vacuum scale or for the flow meter as the case may be. The scale for the variable opening may be calibrated experimentally in a-similar manner as the scales of the vacuum and fiow gages.

To provide for the passage of air' from the blower 14 to the vacuum. chamber for blowing through the permeable plate v1 0 to clear its passages from dust, etc. a connection is made from the blower dlscharge by pipe 30 leading into the suction pipe 12, a three-way valve 31 serving to connectthe blower discharge with either the plpe 30 or with the discharge pipe 16. A three-way valve 32 is also interposed between the suction pipe12 and the intake pipe 13 and an intake pipe 33. In normal operat1on th e valves 31 and 32 are adjusted so that air is drawn from the suction chamber and dis- *charged through the pipe 16. When the permeable plate 10 is to be blown out, these valves will be'adjusted so that the blower or exhauster will j suck air in throughthe dischargepipe 33 and will intake through.

the pipes-30 and 12 into the vacuum chamber.

In Figs. 4, 5, 6 and 7, I have illustrated a form of apparatus having a cyl ndrlcal permeable measuring surface provided by the peripheral wall of a rotatably mounted cylinder. up less space in Figs. 1 to 3 and has other advantages for measuring some kinds of surfaces. As shown in these figures, the permeable supporting plate which provides the measurin surface is formed bythe'peripheral wal An apparatus of this form takes than one of the form shown 10 of a cylinder 40. The'ends of the cy-linder are closed so that the interior serves end of the cylinder and is journaled in a suitable bearlng 42, a stufling box serving to make a practically air-ti ht joint aroun the shaft. At the other en of the cylinder 7 v the cylinder head is journaled on a bearing piece 43, passage of air being prevented by suitable packing rings as indicated, and the end of the hollow shaft 41 extends into and has its hearing within the cored out end of the bearing piece 43. The purpose of this form of hearing will be pointed out hereafter. The portion of the shaft 41 within the cylinder 1s formed with intake openings, the aggregate size of which should of course be at least equal to and most desirably somewhat greater than. the aggregate cross-sectional area of the passages through the plate 10*, or of such portion of the plate 10 as serves at one time as the measuring surface. The suction pipe 12 connects with the hollow shaft 41 through the bearin exhausting fan blower. As in the 'case of the apparatus of Figs. -1 to 3, the suction pipe 12 is provided with a regulating valve 15; a vacuum gage 20 is provided for indi- 42 and leads to the exhauster 14*, which 1s here shown as a constant speed eating the degree of vacuum in the suction chamber, that is, the interior of the measuring cylinder 40, this gage being shown in Fig. 4 as connectedwith the intake end ofthe pipe 12; and for indicating the flow of air into and from the vacuum chamber a, flow meter, formed by a Venturi tube 17.

-provided with a mercur gage 18, isconnected with pipe 16 lea ing from the-dischar e of the exhauster; and a variable auxi iary opening 28 to the suction chamber is provided in one of the cylinder heads as Y shown in Figs. 4 and 6.

The cylindrical supporting plate 1O may be of any. suitable character provided it has the necessary uniform permeability and the proper degree of permeability and is of suitable strength. It may be, for example, a perforated metal plate as indicated in Figs. 4 and7, the perforations being of uni-.

form size and uniformly spaced. As'shown in these drawings, the perforations of the plate 10 are proportionately -much. too large. The smaller the perforations and the closer they are together the more accurate will be the results obtained in the use of the i apparatus; and the smaller the perforations the closer they can be arranged without causing the aggregate permeability of the 1 plate to be so great as to require the use of an exhauster and connections of undue size.- But, on theotherhand, the smaller theperforations the more apt they are to become'jiat I more or less clog ed and the more diflicult 1,eas,ose

they are to keep c ear and open to their full capacity, and it is of course necessary for the sheetbeing suitis fed on to the-cyllie flat and smooth surface of the cylinder, ably manipulated as it inder so that it will thereagamst. In this wa the sheet may be very readily and quic measuring surface so as to lie smooth and y applied to the flat thereon. When the sheet is all on the carries a worm meshing with a worm wheel 51 on the hollow shaft 41.

It will usually be more convenient to have the cylinder of such circumferential size as compared to the width of the surfaces to be measured that the sheets to be measured may be fed on to the cylinder from one side thereof as the cylinder is turned, and then after the measurement is completed be fed off from the cylinder at the opposite side by continued rotation. When the machlne is to be so used, it is conveniently provided with a feeding table 52 at one side of the cylinder having an up-turned guiding edge 53 to direct the edge of the sheet to the surface of the cylinder, and with a receiving table 54 at the opposite side of the cylinder provided with an'up-turned guiding edge 55 which extends close to the surface of the cylinder to strip the measured sheetv therefrom and to direct it on to the receiving table. Only the part of the peripheral surface of the cylinder extending above the guiding edges 53 and 55of theta-bles will then be used for supporting thesurface' to be measured, and in order to cut down the aggregate permeability of the peripheral wall of the cylinder, or the plate 10*, it is desirable to provide means for preventing the passage of air into the suction chamber through the unused portion of the permeable plate. A suitably arran ed shield will serve this purpose, and in t e drawings I have shown an inner shield or partition plate 56, the side edges of which extend close against the inner surface of the plate l0 on opposite sides of the cylinder and about on the lines of the edges of the guides 53 and 55, and the ends of which extend close against the inner surface of the cylinder heads. This shield or partition plate is hung on the shaft 41 by collars 5 and the collar 57 at one end is keyed to the bearing sleeve 43 as shown in Fig. 4 to hold the partition plate against rotation with the cylinder.

The apparatus shown in Figs. 4 to? may be used in measuring the surface area of flexible sheets in substantialiy the same way as the apparatus shown in igs. 1, 2 and 3 is used, except that with this a paratus the sheet may be quickly applied to the measuring surface by simply pushing it along the feed table 52 to bring one edge portion thereof against the surface of the cylinder and then by. rotatingthe cylinder with the exhausting means 1n operation causing the whole sheet to be applied to the measuring surface,-

rotation of the cylinder may be stopped and the reading of the gage or gages taken, the, 'exhaustin means being adjusted before reading if this method of using the apparatus is. being followed.

Then-by continued rotation of-the cylinder the sheet will table 54, and the next sheet to be measure be fed off on to the receiving.

may at the same time or thereafter be drawn on to the cylinder and applied to the mess ,uring surface.

Figs. 8, 9 and 10 illustrate a form of cylinder for an apparatus such as shown in Figs. 4 to 7 in which the measuring surface of the cylinder is formed with circumferentially extending slots or passages between spaced annular and comparatively narrow cylinder sections 60.- The cylinder sections, 60 are formed with spokes andcentral collars or hubs to fit on the and the sections mounted spaced apart in'the construction shown in these figures by peripheral spacing pieces 61, and the cylinder sections, and cylinder heads are drawn together and held by tie bolts are of circumferential length to extend only part way about the cylinder, leaving open hollow shaft 41,

on the shaft are spacing pieces 62. The spacing pieces 61 I slotsbetween the sections 60 extending. the

balance of the somewhat greater than one-half the circumference of the cylinder as shown; The

distance about the circum-f ference of the cylinder. The slots will con veniently be of a circumferential length width of the slots and. the width of the faces of the cylinder sections 60 will be proportionately narrower than shown in ig. 8, and the slots will be of a width only a small fraction of the width of the sections,

as will be understood from what has heretofore been explained. The permeable wall or plate l0 provided by forming the cylinder of annular sections as shown in these figures is of greater strength than the wall formed of a perforated plate as shown in-Figs. 4 to 7, and the construction of these figures is therefore better adapted for large apparatus having a large measuring surface and with which a comparatively high vacuum is employed. The construction also has other advantages as pointed out in connection with the fiat bed and 3.

used in t e same way as the apparatus of Figs. 4' to 7, except that as the uniformly permeably measunng surface extends only part way about the cylinder it is necessary apparatus of Figs. 1, 2

The apparatus of Figs. 8, and 10 may be w a neeepeef that the cylindefsliifilb di proper position" when a sheet to be measured'is started tobe fed thereon.

A simple form of apparatus suitable'more especially for measuring small surfaces is shown in Fig. 11. This apparatus comprises two permeable plates 10 and 10 both of the same uniform permeability and of the in the construction shown belng placed side by side and each forming partof the-top wall, of the box. One of the plates, as 10,-

same-size, these plates each forming part of} the walls of a suction boxll" the two. plates serves as a supporting or measurin plate to receive the surfaces to be measure and the.

a other, 10f ,"is" provided with an adjustable cover 7 arranged to close the po'rtion ofthe;

- plate over'whichit extendsyand in conjunci-y tion with the coverjshere is provided a scale f part carried by the box, and the cover being 71, the scale being shown as marked-on a --.provided with. a pointer to cooperate there--- with. ,The scale will be marked to indicatethe areao'f the uncovered portion of the perof the slide-70. -In using this apparatus, the

meable. plate according to .the position exhausting means being in' operation and mam'talning a constant exhaust, the sheet 1 or other thing the surface of'which is to be measured is placedagainst the surface of the -j plate 10, and slide .70 is then adjusted to restore the reading of-the vacuum gage to whatit was-with the cover- 70 entirely closed and with tlie plate 10 entirely unobstructed. When the cover 70 has been thus adjusted-to restore the reading of the vacuum gage, the area" of the exposed portion of the-plate 10 will of course. be equal l to the area of the, surface tonbe'measured applied to the plate 10-,-.and this area will beindicated on the scale 71'. An advantage of this form of a paratus-is that the scale 1 Obviously, 'the coven-might be adjusted I 171 may be marke directly according to the area of exposed portions of the plate 10 with the slide 70 in the various positions.

' Ti -according to indications of a flow meter instead of -1nd1cat1ons of a vacuum gage.

\ I I Myflmethod and apparatus are obviously adaptedjfor measurement of all kinds of surfaces which may be applied to and which i come within thelimits 'of the measuring sur-v face of the apparatus. The method and apt! paratus arev of course" especially adapted for 55.

measuring ,thesurface area of sheets of material,and especially more or less flexible sheets I and sheets which are impervious to the passage therethrou'gh of air under the suction tion employed need not be high, but should bathe-suction which shouldbe used for ac- -'cur ate'results. For. example, in "measuring the areas of heavy hides, a stronger suction v: is naturally required than in measuring comhe degree of suction required is readily determined for any class of sheets or other things the surfaces of which are to be measp aratively flexible sheets. of soft leather.

ured. As the indicating device of the apparatus will usually be calibrated empirically,v

.-thefuse of. the method and apparatus is not limited strictly to .measurement of surfaces of sheets or other things which are entirely impervious"-to air under the suction employed, it being only necessary that the sheets tobemeasured shall be substantially less permeable than the measuring surface and that they shall be of approximately uni-- form permeability, and that the indicating devices of the apparatus used shall be calibrated for the particular sheets to be measured or for sheets of thesame permeability as the. sheets to be measured.

As above pointed out, it is of course necessary that the contact of the measuring surface with the surface to be measured shall be such as to 'close against access of air the portion of the measuring surface covered by the surface 'to be measured. This result is -readily secured through the suction due to the partial .vacuum in the vacuum chamber when the surface to be measured is possessed of sufiicient flexibility to accommodate itself to the measuring surface. But if the surface to be measured is inflexible and not capable of-accommodating itself to themeasuring surface, then it is desirable to provide the permeable measuring plate with a surfacewhich is yielding to a slightdegree sufiicient to cause it to accommodate itself to the surface to be measured. For'this purpose, the supporting or m'easuring'plate maybe formed as illustrated by Fig. 12, in

which a perforate supporting plate 10' is provided. with a yielding and flexible surface plate 10" having perforationsregistering with the perforations of the supporting plate 10 and which may be formed of india rubber of a suitable degree of flexibility or of other suitable yielding and flexible material. The perforations of the flexible plate 10 should be of such size relatively to the thickness of the plate that they will not beclosed when the plate is compressed, and

should best be of outwardly as shown.

What is claimed is: 1. The -method. of measuring surface tapered shape areas, which consists in placing an object with its surface to be measured against a fluid permeable .measuring surface of a definite size and of uniform permeability per unltof area, and determining the area of the surface to be measured from change in the conditions of flow of a fluid through the measuring surface under a difference in due to the m Q. g pressure on opposite sides of said surface presence against the measuring surface of'the surface to be measured.

2. The method of measuringv surface areas, which consists in maintainmg a par- .tial"- vacuum on vone side of a permeable,

plate of definite site and uniform permeplate dueto the presence I prises means providing a measuring stir-- ability per unitarea', placing an object with its surface to be measured against the oppesiteside of said plate, and determining .the

area of the surface to bemeasured from the change in aggregate permeability of the\ thereagainst of the surface to be measured. v

i 3. The method. of measuring surface areas by means of an apparatus which com- ."face of uniform permeability er unit of area, means for mamtainin a ifi'erence in pressure ofxa fluidon opposite sides of sa1d measuring surface, a pressure gage controlled according tothe difference'm pres sure 'on opposite-sides of the measuring sur- -Iface,

to'the flowof' 'ing surface,

flow gage controlled according said fluid through the measurwhich method consists in Y placing an"object with its" surface to be measured against the measuring surface, adjusting the difference in pressures on opposite sides of the measuring surface to restore one of said gages to its initial reading, and determining the area 'of'the surface to be measured from the reading of the other gage. I. p I

' -42. Apparatus for'measuring surface areas, comprising in combination means providing a permeable measuring surfaceof'uniform permeability er unit of areaadaptedto.

have the sur ace to be -measured placed thereagainst, and means for measuring the change in aggregate permeabilityv of said measurin surface due to the presence thereagainst 0 the surface to be measured.

5. Apparatus for measuring surface areas,- comprislng in combination means providlng a permeablemeasuring surface of uniform permeability er unit of area adapted to have the, sur ace to. be measured placed thereagainst, and means for measuring the change in aggregate permeability of said against of the surface to be measured, said measuring means including indicating means for indicating the change in aggregate permeability in terms of surface area of the part of the measuring surface covered by the surface to be measured.

6. Apparatus for measuring surface areas,

I comprising in combination means providing a permeable measuring surface "of uniform permeability per unit of area adapted to have the surface to be measured placed thereagainst, means for maintaining a difference in pressure of a. fluid on opposite sides'of the measuring surface, and meansfor determining jthe area of the surface to be measured fromv change in the conditions s of flow of said-fluid through the measuring surface due to the th measuringsurface. i g 8. Apparatus for measuring surface areas, comprisin in combination meansroviding v a permeab e measuring surface of uniform permeability per unit of area adapted to have the surface to be measured placed thereagainst, means for maintaining a difference in pressure of a fluid on opposite sides of the measuring surface, and means for measuring the loss in aggregate permeability of the measuring surface due to the presence thereagainst of the surface to be measured including a pressure gage controlled according to the difference in pressures on opposite sides of the measuring surface and calibrated to indicate the loss in aggregate Y ermeability in terms of surface area of t e part of the measuring surface covered. by the surface to be measured.

' 9. Apparatus for measuring surface areas, comprising in combination means providing a permeable measuring surface of uniform permeability per unit of area adapted to have the surface to be measured placed thereagainst, means for maintaining a difference in pressure of a fluid on opposite sides of the measuring surface, and means for measuring the loss in aggregate per, meability of the measuring surface due to the presence thereaga'inst of the surface to be measured including a flow ga e controlled Y according to the flow of said uid through the measuring surface and calibrated to indicate the loss in aggregate permeability in terms ofsurface area ofthe part of the measuring surface covered by the surface to be measured.- V

10. Apparatus for measuring surface areas, comprising in combination means providing a permeable measuring surface of uniform permeability per unit of area adapted tohave the surface to be measured piaced thereagainst means for maintaining a difference in pressure of a fluid on opposite sides' of the measuring surface, and means for measuring the loss in aggregate permeability of the measuring surface due to the presence thereagainst of the surface to be measured including a pressure gage controlled according to the difference in ressures on oppositesides'of the measurmg surface and a flow ga econtrolled according to the flow of said uid through the measuring surface. 11. Ap aratus 7 viding a permeable measuring surface of uniform" permeability per unit f, of ,,area

adapted to have. the surface to be measured placed thereagainst,'adjustable means. for; maintaining a-fdifference' in pressureof a,I fluid on opposite sidesof the measuring surface, and means for measuring the loss in aggregate permeability-of the measuring due to the presence thereagainstof surface v the surface to be measured mcludmg a pressure gage controlled according to the difference in pressures on opposite-sides of the measuring surface and a flow ,jgage; conhrough the measuring surface. 1,

,areas,

"air, from the trolled according to the flow oflsa d,

12. Apparatus for measurif g; surface ity per unit of area, a suction chamber of which saidsupporting-"plate forms a part ofthe inclosing wall, means for exhausting suction chamber, a vacuumgage controlled by the pressure in the suc-f tion' chamber, anda flow meter controlled 7 by-the air sucked-from the suction chamber.

'- 13. Apparatus ;;for measuring. surface.

ty. per unit of:jarea,.:a suctionchamber of Wh1ch's'aid' supporting plate forms a part of theinclosing wall,"means for exhausting I ch'amber,land a flow 'metercontrolled by. the air sucked from the airflfrom the suctionsuction chamber. --I1 I 14. Apparatus -for measuring fsurfac'e' areas, -compris ngin COIIlblIlfitlOD- a perms;

able 'supportin' 'plateof uniform permeabily P9 whichlsaid'supporting plate forms ation chamber.

15. Apparatus surface" 'combination a permeablejsupporting pl teef uniform permeabi1-.

areas, comprisingii ity .per, unit 1 of i area, a I suction I chamber of which said supporting p chamben I 1 16. Apparatus able supportin it per'unitj o which js for measuring fsurfacef; areas, comprising n combination means procomprising in combination a permev able supporting plate of uniform. permeabil-,

, able support1 areas, i compri sing in combination a permev able supporting plate of uniform permeabilfrom the suctlonchamber, a gage--'forfindi-.

' catlng the. conditlons of'flow oftheai throng :the supporting plate, and means/ii" opening will indicate the area of the unit'o i area, a suction chamber of.

\ part or; the mclosmg' wall,- means for exhausting air from the suctionchamber, andag' vacuum gage" controlled by, the pressure; ,in. the sac late forms" a. part-v of 5- the inclosing wall,iadjustable meansioreit-gi. hau'stingair from the suction chamber, vacuum gage controlled by the pressure. the suction chamber, and a flow meter controlled by the air sucked from the, suction "supportingplate of uniform" permeability a suction Ichamberof which f per unitof area, V said supporting plate forms a part: of the. }..fl

for measuring} "surac plate of uniform permeabilarea, a suctionchamber ofsupporting plate forms a part of y chamber.

' ILApparatus for; 'measurin g' surface areas, comprising in combinationa permeable supportin pl ate of uniform permeabil- -ityfper unit 0 area, 'a suction chamber of ch said supporting plate forms a part of the -inclosing wall, means for exhausting'air' fromthe suction chamber, a flow metercon-V- trolled by the'air sucked from the suction.

openin to the suction chamber.

chamber,, and means providing avari'able from'the suction chamber, a vacuum gage .v

controlled by the; pressure in the suction chamber, andmeans providing aflvariable l openin to the suction chamber.

19. pparatus for measuring surface areas comprisingj in combination a permeng pl tel of uniform permeabilthe inclosing-wall, means'for exhausting air providing a variable opening to-thesuction, chamber whereby when a surface to bemease 1 ured is laced against the supporting .plate the] con restore the reading'of the-gage toits origi- I J:

itions of flow may be adjusted'to nal value so that the adjustment of, said face being measured.

20. Apparatus for measuring surface areas, comprising in combmationa permethe inclosing wall, means for exhausting air from thevsnction chamber, a gage for indipresencethereagainst of the-surface to be measured, and means for reducing the range v of .thepgage reading by an amount equivag lent to a certain surface area? V 3 for measuring ,suface areas, comprising in 'combination'a permeable: 125-.-

21. Apparatus 'sur 7 5:

Fable supporting plate'of uniform. permeabil 7 ity per umt of area, a suction chamber of which. said supportingplate forms apart of ing change in theconditionsofflow of airthrough the supporting plate due to the v 1n clos'1ng;,wall,. means for. jeXhaustingTair ity per unit of area,.'ja suction-chamber of air through the supporting plate due to the presence thereagainst of the surface to be measured and means providing a closable auxiliary opening to the suction chamber for reducing the range of the gage readings.

per unit of area, a suction chamber of which said supporting plate forms a part of the inclosing Wall, means for exhausting air from the suction chamber, a gage for indicating change in the conditions of flow of slots extending therethrou'gh to form a per meable support of uniform permeability'per unit of area, a suction chamber of which said supporting plate forms a part of the inclosing wall, means for exhausting air fromthe suction chamber, and means for determining the area of the surface to be measured from the change in the conditions of flow of air through the permeable supporting plate due to" the presence there-- against of the surface to be measured.

24. Apparatus for measuring. surface areas, comprising in combination a permeable supporting plate comprising a plurality of narrow bars of equal width equally spaced apart, a suction chamber of which said supporting plate forms a part of the inclosing wall, means for exhausting air from the suction chamber, and means for. determining the area of the surface to be measured from the change in the conditions of flow of air through the permeable supporting plate due to the presence thereagainst of the surface to be measured.

' 25. Apparatus for measuring surface areas,co mprising in combination a permeable supporting plate comprising a pluralityof removable relatively thin bars set flatwise to each other, spacing pieces between said.

bars to provide narrowslots or air passa es between the bars and clamping means or pressing the bars and spacing pieces together, and means for determining the area of the surface 'to be measured from the change in the conditions of flow of air through the permeable supportin plate due to the presence thereagainst of t e surface to be measured.

26. Apparatus for measurmg surface Apparatus for measuring surface, areas, comprising in combination a permeable. supporting plate of uniform permeability areas, comprising in combination a permeable supporting plate having a plane supporting surface comprising a plurality of thin straight bars of metal set on edge flatwise to each other and equall spaced apart, a suction chamber of whic said supportin plate-forms a part of the inclosing wal, means for exhausting air from the suction chamber, and mean for determining the area of the surface to'be measured from the change in the conditions of flow of airthrough the permeable supporting plate due to the presence thereagainst of the surface to be measured.

27 Apparatus for measuring surface areas, comprising in combination a permeable support having a yielding and flexible surface adapted to accommodate itself to slight unevennesses in the surface to be measured, means for maintaining a difference in pres sure of a fluid on opposite sides of the measuring surface, and indicating means controlled according to the conditions of flow of the fluid through the permeable support.'

28. Apparatus for measuring surface areas, comprising in combination a permeable support having a surface portion of yielding and flexiblematerial formed with outwardly flaring openings therethrough, means for maintaining a difference in pressure of a fluid on opposite sides of the measuring surface, and indicating means controlled according to the conditions of flow of the fluid through thepermeable support.

29. Apparatus for measuring surface areas, comprising in combination a permeable supporting plate of uniform permeability per unit of area, a suction chamber of which the supporting plate forms a .part of the inclosing wall, an exhauster connected to the suction box, a suction regulating valve between the exhauster and the suction box, and means for indicating the conditions of flow of air through the supporting surface.

30. Apparatus for measuring surface areas, comprising in combination a permeable supporting plate, a suction chamber of which said supporting plate forms a part of the inclosing wall, means for exhausting air from the suction chamber, and means for vreversmg the air current through the permeable plate.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses. I

CHARLES E. I LUCKE.

' Witnesses: I I

vH; L. KENT, Pam. H. Fmmm. 

